Conducting polymers have been used to modify electrode surfaces and to immobilize enzymes to construct[unreadable] biosensors for the detection of biomedically important species such as nitric oxide(NO), glucose, histamine,[unreadable] etc. We will use other substrates such as nanomaterials including nanotubes and nanoparticles, silica solgel,[unreadable] surfactants, and self-assembled monolayers (SAMs) to modify electrode surfaces for the immobilization[unreadable] of biomolecules in order to develop sensors for biomedically important species such as NO, thiols, histamine,[unreadable] and calcium. During the current grant period we have successfully measured the formal potentials of[unreadable] myoglobin and cytochromes by direct electrochemistry at electrodes modified with those substrates. We will[unreadable] use this approach to study several novel proteins such as pirin, decarboxylase enzymes, and diheme[unreadable] proteins by collaborating with two biochemistry professors at the University of Mississippi Medical Center.[unreadable] The hypotheses for the study are as follows:(1) the electrodes modified with those substrates help to carry[unreadable] out direct electrochemistry of novel proteins, and (2) the novel proteins on (or in) those substrates maintain[unreadable] the native form or at least these proteins are not denatured. Electrochemical methods such as cyclic[unreadable] voltammetry (CV), differential pulse voltammetry (DPV), and square wave voltammetry (SWV) will be used to[unreadable] determine the formal potentials of those proteins on (or in) different substrates. Electrochemistry will also be[unreadable] used to probe the interaction of the metal center (e.g., Fe) with dioxygen, NO, and the related transcriptional[unreadable] cofactors such as P50. These studies will help to find protein/matrix systems which may provide a fast[unreadable] electron transfer rate between the protein molecule and the substrate for the development of more sensitive[unreadable] transducers. These electrochemical studies will also provide valuable information for the protein chemistry[unreadable] involved in biomedical research. Those protein molecules on the modified electrodes as well as in solutions[unreadable] will also be characterized by spectroscopic methods including laser-Raman, FT-IR, UV-vis, atomic force[unreadable] microscopy (AFM), TEM, and SEM. These studies will provide spectroscopic evidence for the interactions[unreadable] between enzyme proteins and the modified electrodes and may be able to explain the differences.in[unreadable] electrochemical behaviors of protein molecules on different substrates.[unreadable]